1. Field of the Invention
The present invention relates to product inspection and grading. More particularly, the present invention relates to a method and apparatus for detecting and intercepting an irregular product in a product flow.
2. Description of the Prior Art
Most products are graded according to quality. Agricultural products, such as fruits, are no exception. Several factors influence the grade assigned to agricultural products. In the case of fruit, firmness is an indication of quality. If the fruit is very hard, it may not be ripe; if the fruit is very soft, it may be overripe or rotten.
Many fruits, especially drupaceous fruits, including prunes and apricots, and other fruits, such as dates, are processed before being brought to market. Such fruits are often pitted and/or dried. The grade of such processed fruits is influenced by the firmness of the fruit's flesh and by the presence of residual pit material.
In a batch of pitted fruit, there will always be some fruit in which a pit or a portion of the pit remains. The grade of the fruit is accordingly reduced if there is a significant amount of pit remaining with the fruit. Residual pit material in the pitted fruit also presents a safety hazard. A consumer of the product may not expect to encounter a pit. Biting into a pit unexpectedly may damage the consumer's teeth; unexpectedly swallowing a pit or piece of pit may cause more severe problems.
Inspecting fruit for ripeness and for residual materials, such as pits, is a labor intensive, imperfect process. To thoroughly hand inspect every piece of fruit in a product flow would require so much labor input as to raise the production price of processed, pitted fruit beyond its market value.
There has heretofore been no apparatus or method provided for inspecting fruit in a product flow on an individual basis wherein the inspection process does not, itself, degrade the quality of the fruit. U.S. Pat. No. 4,146,136 issued to Ross, et al., entitled, FOOD DETECTOR FOR FOOD PRODUCTS, is typical of the devices that have been available for pit detection. Such devices squeeze the food product through a narrow passage. Food products containing pits do not readily pass through the passage and are therefore detected. A disadvantage of a device of this type is that the fruit must be mauled to detect the pit. Such mauled fruit is of a lower grade and is therefore of less value in the market. Additionally, such devices are generally not useful in grading fruits according to ripeness.